North Korea has not acknowledged the dead man's identity but has repeatedly criticised the murder investigation and autopsy, accusing Malaysia of conniving with its enemies.

"They have conducted the autopsy without the consent and attendance of the DPRK (North Korea) embassy and later arrested a DPRK citizen without any clear evidence showing his involvement in the incident," ambassador Kang said.

South Korea has blamed the North for the murder.

It cites what it says was a standing order from leader Kim Jong-Un to kill his exiled half-brother, who may have been seen as a potential rival.

In a sign of the security tensions, police armed with assault rifles cordoned off the entrance to North Korea's embassy in Kuala Lumpur before the envoy left.

Kang departed in a black chauffeured Jaguar -- the North Korean flag which denotes an ambassador was removed from its bonnet.

He checked in a Philips TV, three suitcases and four boxes vacuum-wrapped and marked with the words "DPRK Pyongyang".

Senior government officials told AFP he left at 6.25 pm (1025 GMT) on flight MH360 for Beijing, shortly after the deadline for his expulsion at 6 pm.

He landed in the Chinese capital in the early hours of Tuesday morning, leaving the airport via a VIP exit surrounded by security, AFP journalists at the scene said.

He was then whisked away in a North Korean diplomatic car to Pyongyang's vast embassy complex in central Beijing, where he was expected to spend the night before flying on to North Korea.

- 'Hostile forces -

Malaysia had declared Kang persona non grata on Saturday and gave him 48 hours to leave the country after he failed to apologise for his criticism of the investigation.

The diplomatic dispute erupted last month when police rejected North Korean diplomats' demands to hand over Kim's body.

Kang then claimed the investigation was politically motivated and said Kuala Lumpur was conspiring with "hostile forces" -- a reference to the North's arch-rival, Seoul.

Malaysia summoned Kang for a dressing-down, with Najib saying the ambassador's statement was "diplomatically rude".

Malaysia has also cancelled a rare visa-free travel deal with North Korea. It ordered the ambassador expelled after he failed to present himself at the foreign ministry when summoned on Saturday.

The foreign ministry has said the expulsion is "part of the process by the Malaysian government to review its relations" with North Korea.

The row also extended to sport, with Malaysian football authorities banning the national team from playing an Asian Cup qualifying match in Pyongyang -- citing security threats in the wake of the expulsion.

Police are seeking seven North Korean suspects in their probe, four of whom left Malaysia on the day of the murder. But on Friday they released the only North Korean they had arrested for lack of evidence.

Two women -- one Vietnamese and one Indonesian -- have been charged with the murder. Airport CCTV footage shows them approaching the heavyset 45-year-old and apparently smearing his face with a cloth.

Police say he suffered a seizure and died less than 20 minutes later. Swabs of the dead man's face revealed traces of the VX nerve agent.

S Selvam, Huong's lawyer, suggested Monday that Malaysia does not have the expertise to identify the VX nerve agent.

He added that he would write to Malaysia's police chief asking for another autopsy.

"How is (it) that my client is accused of using VX nerve agent in her hand and applying it to the face of the deceased and not suffering any illness herself?" he told AFP.